1. Field of the Invention
The present invention relates to a lens drive apparatus.
2. Description of the Related Art
Conventionally, there has been known a lens drive apparatus including a holder and a cam member. The holder is movably supported in the optical axis direction and hold a lens, and the cam member moves the holder in the optical axis direction (see Japanese Unexamined Patent Application Publication No. 2005-195678).
There is known a lens drive apparatus into which a lens is assembled in situ. FIG. 5 is a cross-sectional view of the aforementioned conventional lens drive apparatus. The conventional lens drive apparatus includes: a base member 10P; a cover member 20P; a guide rod 30P, a holder 40P; a cam member 50P; a biasing member 60P; a motor unit 70P and a gear 90P. The driving of the motor unit 70P allows the cam member 50P to rotate via the gear 90P. The cam member 50P has a cam surface 51P, and the cam surface 51P comes in contact with a cam follower 45P. The biasing member 60P urges the holder 40P toward the cam member 50P. Additionally, the holder 40P is movably supported by the guide rod 30P in the optical axis direction LA. Therefore, the rotation of the cam member 50P allows the cam surface 51P to activate the cam follower 45P, whereby the holder 40P moves in the optical axis direction LA.
In the conventional lens drive apparatus, a lens frame (not shown) holding a lens is inserted into the holder 40P in an inserting direction shown in the drawing, so that the lens frame is assembled into the holder 40P. Additionally, an opening 41P is formed in the holder 40P and a thread portion is formed at an inner periphery of the opening 41P. Likewise, a thread portion is formed at an outer periphery of the lens frame. The lens frame is inserted into the holder 40P and is rotated, thereby adjusting the screwing amount, and defining the position of the lens frame relative to the holder 40P.
However, in such a lens drive apparatus, when the lens flame is inserted, the holder 40P is pushed to the image pickup device side, and the pushed load concentrates on the cam follower 45P and the cam surface 51P. Thus, the parts, such as the cam follower 45P and the cam member 50P, are deformed and the accuracy thereof is degraded. As a result, the variation in the positional accuracy of the lens and the operational defect might occur.